1. Field of the Invention
The present invention provides an economizer by utilizing air-to-air heat exchange between the hot gases flowing up the exhaust flue of a hot air gas furnace and the cold air return which supplies air for heating. With the high cost of energy the additional savings created by making use of the heat in otherwise exhausted hot gases is quite beneficial in increasing the operating efficiency of hot air gas furnaces.
In an effort to increase the efficiency of such hot air gas furnaces many devices have been conceived to make efficient usage of this normally exhausted hot air. No device within this field has yet been designed which makes usage of conventional and readily available low cost parts to be used in the fabrication of a device for increasing the efficiency of a gas furnace. The present invention provides such a device.
2. Description of the Prior Art
A large number of patents have dealt with the problem of making efficient usage of the heated gases normally expelled out of the flue up the chimney with a gas hot air furnace. Examples of such U.S. Pat. Nos. are listed as follows: 459,395; 649,251; 1,953,302; 2,035,341; 2,143,287; 2,348,569; 2,573,364; 2,874,943; 2,893,705; 3,198,190; 3,916,991; and 3,993,244. The U.S. Pat. No. 3,198,190 discloses a system which recirculates vented gases in a furnace whereby the hot gases are recombusted to reduce carbon monoxide therein. As such that design deals with pollution rather than energy savings and as such is not applicable to the present invention.
The U.S. Pat. No. 3,993,244 discloses a system for increasing the flow of heat by decreasing the loss of heat through the venting ducts which is achieved by utilizing flow through an auxiliary non-gaseous heat conducting member. As such this sytem does not provide a means for increasing the temperature of the incoming air traveling through the cold air return.
U.S. Pat. No. 3,916,991 discloses a three conduit system including an inner conduit comprising the main vent of the furnace to the chimney with another conduit configured therearound to extract heat thereform and a third conduit encompassing both the first and second conduits to gather the heated gas passing by the second conduit to carry the heat to the chimney. This system is designed to increase heating at any remote location and does not use the boiling and condensing thermal transfer affect as disclosed in the claims of the present invention.
No system of the prior art has yet been described which utilizes conventional low cost parts and the ease of installation which is inherent with the design of the present concept. This invention provides a means for directly communicating heat normally lost through the exhaust flue to be utilized efficiently in the heating of the air traveling through the cold air return and as such is a novel concept.